The rational for the present invention is based upon several factors that interplay against the transmittal of oxygen and removal of carbon dioxide.
Many patients with COPD adopt a rapid, shallow breathing pattern, frequently with chest wall and abdominal asynchrony. In patients with hyper-inflated lungs and an increased expiratory reserve volume (ERV), the inspiratory muscles are in a permanently shortened position which creates a poor length-tension relationship.
Despite some adaptation of the muscles to this shortening, inhalation is augmented by the accessory muscles of respiration, with fixation of the shoulder girdle. Although by fixing the shoulder girdle, thoracic volume can be increased and ventilation improved, respiratory muscle oxygen consumption is increased.
By using an anesthetic along with gases having a reduced density supplemented with increased oxygen, rates of flow of gas time travel are reduced and the resistance encountered by COPD patients is relieved by the reduced density of gases within the conducting airways. Using too much reduced density adversely affects the flow and the pressure in the deepest lung fields which are left shut, and bypassed.
Historically, using very low density heliox in COPD patients allows ease of work of breathing, but decreasing the density of the gases too low, increases the velocity in blocked and semi-blocked communicating airways having reduced diameters causing increased turbulence resulting in forward eddy formation and causing air clutching and non-delivery of critically fresh inhaled gases. This braking of the air just behind the forward fast gases causes back pressure and increases pressure to slow the transmittal of gases. This increases inspiratory time, thus further limiting exhalation time and the removal of waste gases. Slowing the transmittal of gases prevents the opening up of collapsed and unexpanded alveoli in the depth of the lung fields.
High heliox concentrations, meaning concentrations having helium above 60 percent, increase turbulence by reducing the gas density such that its velocity in damaged, blocked, and semi-blocked distal airways found in the lower airways of the lungs in combination due to the increased lung volumes found above normal, there in the most distal communicating airways closest to the alveoli, where actual gas exchange between outside air and internal bloodstream occurs, the pressure driving gases is factually increased as is the resistance to local airflow. It is here that the radius and density becomes highly relevant to COPD patients. Therefore, the present invention reduces the density of heliox, but reduces the density moderately such that it is near the density of air which allows for the greatest push per volume change in the areas most proximal to the gas exchange pores, known as “pores of khan”, contained within the alveoli where actual gas exchange of air inhaled from outside the lungs enters the bloodstream and supplies needed oxygen to counter the muscular increases of oxygen usages found.
Many patients who have complications related to obstructive and/or restrictive airways experience increased damage to the lung's elastic ability. Obstructive airway diseases involve the two large bronchi, left and right branches and down, via multiple generations of branching smaller communicating airways. Such airway generation branching is commonly considered to have 23 generations that reach into the lung fields down until the “Alveoli”—the lungs ‘air sac's,’ where blood-air-gas-exchange occurs.
Chronic obstructive pulmonary (airway) disease, known as C.O.P.D., includes dysfunctions of those airways also termed “airway disease” which includes asthma, emphysema, secondary pulmonary restrictions, and obstructive components to airflow as found in lung parenchyma fibrosis and cystic fibrosis.
As well as following lung disease, segmental resections and or post chest wall traumas, fall under this encompassing title, specifically in this application most under common medical heading's of Chronic Obstructive Pulmonary Disease (“COPD”).
Two types of inhaling medical devices are currently used for treating patients experiencing breathing difficulties. One device, typically given at a hospital, is known as a hand held nebulizer or HHN. This type of device uses a large metal tank connected to an oxygen line for supplying oxygen to the patient. This type of device is not portable.
The other device is a portable device used out of hospital commonly called a “rescue inhaler” and also known as a metered-dose inhaler or MDI. Both devices dispense inhaled drugs in the form of an aerosolized medication, typically airway opener drugs which are designed to open lung airways which carry air to the recesses of the lungs where the fresh air interacts with the air sacs within the lung tissue. These airway opener drugs are given to counteract airway spasms and or constrictions.
Both types of inhalers usually spray into the user's mouth. Said aerosolized medication is designed to combat airway spasms and diameter changes within the lung's airways when inhaled. Without such treatments, a patient will have to increase their work of breathing and rate of breaths in order to supply oxygen to their lungs. At severe times, patients are unable to breathe on their own without the assistance of such devices, and if left untreated, will go into respiratory failure requiring them to be placed onto a ventilator for supportive breathing along with oxygenation supplementation.
Thus, airway opening drugs are dispensed as an aerosol under pressure and are inhaled by a patient to aid breathing which has been affected by airway flow restrictions due to asthma, bronchitis, emphysema, asthmatic bronchitis, cystic fibrosis, and chronic or acute allergic complications.
Metered-dosage inhalers carry medicine within a light metal pressurized canister. Such medicine is usually an aerosolized medicine typically consisting of a beta-adrenergic designed airway opening drug. Some examples include Salbutamol and Albuterol. These aerosolized medications are sprayed outward toward a user's mouth for inhalation Inhaled aerosolized steroids may also be used.
Without such devices along with their inhaled drugs, patients would suffocate thus leading them to be hospitalized, intubated, and placed onto ventilatory support. An exacerbation of asthma, when severe, is life threatening.
Typically mediations inhaled by prior art units such as an MDI are dispensed in a pre-selected quantity that is not always optimum for a patient's airways. This is due to medication being lost from impacting the back of the throat during the higher inspiratory phase of the respiratory cycle. This could lead to a greater cardio tropic effect which is dangerous: the lost medicine contacting the throat of the patient produces a greater load on the heart due to the large amount of blood vessels at back of the throat. The danger occurs physiologically when such medicines dissolve into the blood vessels in the back of the throat when lost as during the higher inspiratory phase. In this case, a hand held nebulizer is better than a metered-dose inhaler because it delivers a lower quantity of medication over time which allows the airways to progressively open at lower dosages.
However, hand held nebulizer cannot be carried by an individual person, such as for when they are walking down the street, because they are much less portable than a metered-dose inhaler. Rather, a patient is most commonly transported on emergency basis to a hospital where they receive a hand held nebulizer treatment. Hand held nebulizers provide longer treatment times by continuously spraying aerosolized medicine for inhalation by the patient. This allows for better treatment for reversing and stabilizing airway deficiencies above that of a metered-dose inhaler where each spray is activated by the user as a push on the medicine canister into its canister holder.
Hand held nebulizers are the standard treatment modality when an individual is hospitalized. Typically, respiratory therapy departments will instruct staff to give hand held nebulizer treatments to their hospitalized patients according to a time schedule. Such time schedules are often inappropriate to the condition of the patient at the time the staff arrives to implement the treatment because the patient may not require a treatment at that time. Yet, the patient may still receive the hand held nebulizer treatment as a prophylactic measure which, although is logically sound, is inherently harmful because it may lead to overwork of the patient's cardiac system and the patient's airways often become less responsive to the drugs dispensed by the hand held nebulizer.
In view of the above, patients are the best to judge their air way hunger and insufficiency at a particular time, and are in the best position to know when to give themselves an HHN treatment. However, patients, such as those in a hospital setting, are often unable to give themselves HHN treatment because they are restricted by IV lines and other medical instruments, and are also often immobile due to a physical condition.
As a consequence, patients suffer by having to take an HHN treatment when many times they are asymptomatic and not in need. This is also unfavorable for caregivers who have to care for other patients, but are required by hospital metrics and third-party reimbursement rates to give the HHN treatments to patients who are clearly asymptomatic and do not need HHN treatment. Thus, irregardless of the patient's actual airway status, HHN treatments are given even though the patient may experience increase heart rates, nervousness, and lack of sleep. This may also lead patient to develop tachyphylaxis which is a decreased response to the medicine given over a period of time so that larger doses are required to produce the same response.
The powering of a hand held nebulizer is typically by compressed air or oxygen supplied by transfer lines running through a hospital's walls, and having an outlet next to a patient's bedside. Said gases are compressed prior to release and are supplied from outside the hospital, either by a band of high pressure gas cylinders connected to a common outlet controller or supplied by a bulk system such as a liquid gas oxygen supply, which in tandem with a vaporizer, supply the oxygen gas to the hospital.
The hand held nebulizer is connected to the patient's bedside with a transport tube providing air or oxygen from an oxygen or air outlet attached via a flow meter designated for each gas. The transport tube is a thin walled supply hose that connects to the gas outlet for supplying the compressed air or oxygen to the patient, and thus powers the hand held nebulizer pneumatically.
There are electrical powered hand held nebulizers, but these nebulizers are still connected to a compressed air almost exclusively without oxygen supply for supplying the gas mixture to the patient. The hand held nebulizer has a reservoir cup where the liquid medicine is placed at a specific dose which is determined and supplied by a self-contained plastic dosage container with a removable top used to fill the nebulizer reservoir. Once the reservoir is filled, the medicine dosage container is discarded. The medicine is then suctioned up via capillary action and brought to a jet nozzle designed for atomization of the contained medicine so that it can be sprayed in small particles as an aerosol.
From these combined parts and actions (e.g., capillary suction and a jet nozzle powered by an external gas supply), an aerosol is generated for the patient to inhale by holding the nebulizer to his/her mouth if capable. Otherwise, a health care provider may assist the patient in holding the nebulizer. In another form, a user wears a mask for inhaling the aerosol medication from the nebulizer. In either form, a patient inhales the aerosol with the suspended medicine at the patient's rate of breathing, called respiratory rate, and depth, called tidal volume.
In contrast to the nebulizer, a metered dosage inhaler has within itself the powering mechanism which is a self-contained cartridge under pressure having a propellant along with the medicine to be inhaled.